Java-File

• Read stdin
  • import java.util.Scanner
  • Scanner in = new Scanner(System.in);
  • data a = in.nextData(primitive type/ Wrapper class data)
    • read String: in.next();(white space delimiter)
    • read whole line as a String: in.nextLine():(enter delimeter)
    • transfer data:
      • exp. String -> int : Integer.parseInt(String)
• Read from file
  • File inputFile = new File(“fileName”)
  • Scanner in = new Scanner(inputFile)
  • then use Scanner method nextData()/hasData()
  • add in.close by the end of project
• Output to File
  • PrintWriter out = new PrintWriter (“out.txt”)
    • if out.txt exist, it will clear to blank
    • if not, it will been create
  • out.print/out.println/out.printf
  • add out.close by the end of project
• Exception
  • for input: “FileNotFindException”
  • for output: User may not allowed to create or overwrite the file in given location
  • throw exception in function
  • when use a path to find file, use two \ instead of one to seperate each level
    • exp. d:\\cmpt270\\out.txt
    • single\+specific character = escape character
      • exp.\n line seperate